The triton charger only charges 1 battery at a time, but it is very nice. I have the older version of it. Also, the wallwarts will charge NiCd or NiMH either one. It's when you get into automatic chargers that shut themselves off when peak voltage has been reached that you need different chargers for the two types of batteries. Basically, NiCd and NiMH peak differently when charging, so if charging a NiMH with a NiCd auto charger, it may not get fully charged before the charger shuts itself off. That's the basic difference.
And when charging, how many volts or cells the battery has makes no difference to the charger, it will (for the most part) charge at a consistent rate regardless. That is, of course, unless we are talking about the very cheaply made chargers. but I wouldn't trust my planes to anything just because it was cheap.